标题： 球形微粒在三维涡流中的输运 显示英文标题

标题： Transport of spherical microparticles in a 3D vortex flow

摘要： 颗粒物在生物和环境流体中很常见，并广泛应用于工业和制药领域。它们的运动和流动动力学受到与周围流体结构相互作用的强烈影响。虽然粒子-流体相互作用在低雷诺数（Re）流动以及完全发展的湍流中得到了广泛研究，但这些颗粒在中间流动区域中的输运机制仍较少被探索。 在这里，我们研究了中性浮力球形颗粒对单一涡旋流场的响应。使用微流控十字交叉几何结构，我们在适度的 $\text{Re}$ （$\sim 50$）下生成了一个特征明确、稳定的三维沿流向涡旋。我们的实验结果得到了数值模拟的支持，表明随着颗粒直径的增加，颗粒逐渐从涡核中排出。起初，小颗粒遵循类似Burgers涡旋的自相似运动，但对于较大的颗粒直径，由于流体惯性和有限尺寸效应，这种趋势出现了偏差。这些发现增强了我们对涡旋流中颗粒动力学的理解，并对涉及颗粒分选和分离的微流体应用具有重要意义。 显示英文摘要

摘要： Particles are common in biological and environmental flows and are widely used in industrial and pharmaceutical applications. Their motion and flow dynamics are strongly affected by interactions with the surrounding flow structure. While particle-flow interactions have been extensively studied in low Reynolds number (Re) flows as well as in fully developed turbulence, the transport mechanisms of these particles in intermediate flow regimes remain less explored. Here, we investigate the response of neutrally buoyant spherical particles to a single vortex flow field. Using a microfluidic cross-slot geometry, we generate a well-characterized, stationary, three-dimensional streamwise vortex at moderate $\text{Re}$ ($\sim 50$). Our experimental results, supported by numerical simulations, show that with increasing particle diameter, they are progressively excluded from the vortex core. Initially, small particles follow a Burgers vortex-like self-similar motion, but for larger particle diameters, deviations from this trend emerge due to fluid inertia and finite-size effects. These findings enhance our understanding of particle dynamics in vortical flows and have implications for microfluidic applications involving particle sorting and separation.